Love is in the air but what’s in your dark chocolate?

Heart shaped boxes of dark chocolates may a no-brainer when it comes to putting a smile on your valentine’s face, but if they have a milk allergy, you may want to think twice before heading to the candy shop.

That’s because a recent study by the Food and Drug Administration (FDA) found that from the 100 dark chocolate products they tested, several of them contained milk. More importantly, on many of these products, milk was not listed on the food label, making it an undeclared allergen.

“This can be a problem, since even one small bite of a product containing milk can cause a dangerous reaction in some individuals,” researcher Binaifer Bedford, M.S., an Oak Ridge Institute for Science and Education (ORISE) fellow at FDA, said in a recent article.

Milk is one of eight major food allergens, along with wheat, eggs, peanuts, tree nuts, fish, Crustacean shellfish and soybeans. U.S. law requires foods containing these major allergens to have their name on the label to help consumers know what is in the food they are eating.

However, undeclared allergens can happen unintentionally when a manufacturer uses the same equipment for separate products without the proper sanitation procedures between production processes. In the case of dark chocolate for example, milk can unintentionally wind up in the product if the same equipment was used previously for making milk chocolate.

According to the article, from September 2009 to September 2012, about one-third of foods reported to FDA as serious health risks involved undeclared allergens, which is also the leading cause of food recall requests by the FDA.

In this particular study, Bedford explains that he and his team of researchers took into consideration the statements and ingredients listed on the labels of various chocolate samples and found the following:

While dark chocolates labeled “dairy free” or “allergen-free” were the least likely to contain milk, two out of 17 of these products were found to contain milk.

All seven samples that declared the presence of milk on the label contained milk; however, 55 (or 59%) of these samples without any clear indication of the presence of milk, were also found to contain milk.

Six out of the 11 chocolate products labeled with “traces of milk” contained milk at detectable levels high enough to potentially cause severe reactions in some individuals.

So, based on these results what can consumers do?

The bottom line, Bedford said, is that Consumers who are allergic to milk should be aware that a high proportion of tested dark chocolates does contained milk.

“Because consumers can’t be sure that a statement about milk is completely accurate, they may want to contact the manufacturer to find out how it controls for allergens such as milk during production,” says Bedford. Information about the manufacturer, packer, or distributor is required to appear on the label of packaged foods.

In addition, consumers can find out what products have been recalled recently on the FDA’s website. For more information, click here.